1. Field of the Invention
The invention concerns new phytosphingosine derivatives and their use in cosmetic compositions.
2. The Related Art
Ceramides represent an important group of lipids, members of which are found in the epidermis of mammals. Skin ceramides are believed to play an important role in water permeability properties, providing an epidermal water-barrier functioning to give increased strength to skin structure and to decrease water loss. Ceramides are N-acylated sphingosine bases. Sphingosine bases are of variable chain length and have the general formula: EQU CH.sub.3 (CH.sub.2).sub.x ACHOHCH(NH.sub.2)CH.sub.2 OH
where A is --CH.dbd.CH-- (sphingosine), --CH.sub.2 --CHOH-- (phytosphingosine) or --CH.sub.2 CH.sub.2 -- (dihydrosphingosine), and where x is generally in the broad range 7 to 27, more typically in the range 10 to 16. Seven distinguishable groups of ceramides have been identified in pig and human epidermis. Each group consists of molecules of varying fatty acid chain length.
Besides naturally occurring ceramides there are substances closely related to them which have been disclosed as components of skin care compositions. For instance, U.S. Pat. No. 5,326,565 (Critchley et al.) reports on a series of novel pseudoceramides which can be prepared at lower cost while still retaining properties necessary to improve water barrier function of the stratum corneum.
Beyond the control of water permeability properties, modified phytosphingosines may have other useful cosmetic properties. Such properties include anti-acne, anti-blemish, anti-bacterial and anti-wrinkle effectiveness.
Accordingly, it is an object of the present invention to provide new types of phytosphingosine derivatives which may be cosmetically useful.
Another object of the present invention is to provide methods for treating acne, blemishes, age spots, fine lines and wrinkles, bacterial growth, oily secretion from pores and the general signs of aging and for lightening (whitening) skin.
These and other objects of the present invention will become more readily apparent from consideration of the following summary and detailed description.